Non-woven fabric for automotive interior skin material and preparation thereof

ABSTRACT

A method for manufacturing a non-woven fabric for automotive interior materials includes printing on at least one of a front surface and a back surface of the non-woven fabric. Alkaline etching is performed on the front surface of the non-woven fabric.

CROSS-REFERENCE TO PRIOR APPLICATIONS

This application is a U.S. National Phase application under 35 U.S.C.§371 of International Application No. PCT/EP2009/005951, filed on Aug.17, 2009, and claims benefit to Korean Patent Application No. KR10-2008-0091649, filed on Sep. 18, 2008. The International Applicationwas published in English on Mar. 25, 2010 as WO 2010/031474 under PCTArticle 21(2).

FIELD

The present invention relates to a non-woven fabric for automotiveinterior materials and a method for manufacturing the same.

BACKGROUND

The interior skin materials for automobiles are manufactured primarilyby plastic sheets, woven fabrics and non-woven fabrics. The plasticsheets have an excellent moldability, but are poor in tactile feeling.In addition, the woven fabrics have a luxurious external appearance andan excellent moldability owing to a low modulus, but the woven fabricsare expensive because they must be used by laminating a PU foam on aback surface thereof due to small thickness. To solve these problems,the non-woven fabrics have been developed and used for interiormaterials for automobiles.

The non-woven fabrics are a type of fiber, which are manufactured byspreading a fiber of a regular thickness and length thinly and broadlyby a carding process, instead of using warps and wefts like cloth,subsequently laminating the fiber in several layers, and combining thelaminated layers by physical bonding, such as needling punching or waterentanglement, or by chemical means, such as coating. Accordingly, thenon-woven fabrics are widely used for the interior materials forautomobiles which are molded in a regular shape by a mold because theyhave a good productivity with low costs compared to the woven fabrics,and have an excellent elongation in various directions. Such non-wovenfabrics for interior materials for automobiles are typicallymanufactured by a needle punching process or a water entanglementmethod. In addition, the non-woven fabrics are currently used aftercoating a binder on a surface or a back surface of the non-woven fabricto impart functionalities, or printing desired patterns or colors on thesurface of the non-woven fabric to diversify the external appearances.

The non-woven fabrics are good in tactile feeling, but relatively poorin external appearance compared to the woven fabrics. In contrast, ifthe surfaces of the non-woven fabrics are processed to improve theexternal appearance thereof, the modulus is significantly increased sothat the moldability is degraded. Accordingly, the non-woven fabrics arenot suitable for the interior materials for automobiles which need avariety of appearances and an excellent moldability. In addition, as thedriving speed of automobiles gets speedier due to the improvement of theengines of automobiles, the sound absorbing properties of the interiormaterials must be improved to provide a comfortable driving environmentduring a high-speed drive, but the sound absorbing properties arereduced if the non-woven fabrics have a smooth surface like most of theinterior skin materials.

Korean Patent Registration No. 10-0771071 describes a method of formingvarious patterns on a woven fabric by an etching method, but it wasavailable only by an etching method using a laser etching apparatus.

SUMMARY

In an embodiment, the present invention provides a method formanufacturing a non-woven fabric for automotive interior materials. Atleast one of a front surface and a back surface of the non-woven fabricis printed. Alkaline etching is performed on the front surface of thenon-woven fabric.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described in even greater detail belowbased on the exemplary figures. The invention is not limited to theexemplary embodiments. Other features and advantages of variousembodiments of the present invention will become apparent by reading thefollowing detailed description with reference to the attached drawingswhich illustrate the following:

FIG. 1 illustrates a principle of an alkaline etching process,

FIG. 2 illustrates the steps of the alkaline etching process aftercoating the surface of the non-woven fabric according to an embodimentof the present invention, whereas

(1) shows a cross-section of the surface coating,

(2) shows alkaline printing,

(3) shows a cross-section after separation,

(4) shows surface coating,

(5) shows alkaline printing,

(6) shows a surface after separation,

FIG. 3 illustrates the steps of the alkaline etching process afterprinting the surface of the non-woven fabric according to an embodimentof the present invention, whereas

(1) shows a cross-section of surface print,

(2) shows alkaline printing,

(3) shows a cross-section after separation,

(4) shows surface print,

(5) shows alkaline printing,

(6) shows a surface after separation,

FIG. 4 illustrates the steps of the alkaline etching process afterprinting the surface of a two-layered structure of the non-woven fabricaccording to an embodiment of the present invention, whereas

(1) shows a cross-section of the two-layered structure of the non-wovenfabric,

(2) shows alkaline printing,

(3) shows a cross-section after separation,

(4) shows a surface of the two-layered structure of the non-wovenfabric,

(5) shows a surface after separation,

FIG. 5 illustrates the step of the alkaline etching process aftercoating the back surface of the non-woven fabric according to anembodiment of the present invention, whereas

(1) shows a cross-section of the back surface coating of the non-wovenfabric,

(2) shows alkaline printing,

(3) shows a cross-section after separation,

(4) shows a surface of the back surface coating of the non-woven fabric,

(5) shows alkaline printing,

(6) shows a surface after separation,

FIG. 6 illustrates a shape of the surface of the non-woven fabric aftervarious pre-treatment of the non-woven fabric according to an embodimentof the present invention, whereas (a) shows the results wherein coatingand printing of different colors are simultaneously performed on thesurface of the non-woven fabric, (b) shows the results wherein coatingis simultaneously performed on the surface of the non-woven fabriccomprising fiber layers each having a different color, (c) shows theresults wherein coating of different colors is simultaneously performedon the surface and the back surface of the non-woven fabric, (d) showsthe results wherein printing is simultaneously performed on the surfaceof the non-woven fabric comprising fiber layers each having a differentcolor, (e) shows the results wherein printing and coating of differentcolors are simultaneously performed on the surface and the back surfaceof the non-woven fabric, (f) shows the results wherein coating issimultaneously performed on the back surface of the non-woven fabriccomprising fiber layers each having a different color, (g) shows theresults where coating and printing are simultaneously performed on thesurface of the non-woven fabric comprising fiber layers each having adifferent color, (h) shows the results wherein coating and printing ofdifferent colors are performed on the surface of the non-woven fabric,and coating is simultaneously performed on the back surface thereof, (i)shows the results wherein coating is performed on the surface and theback surface of the non-woven fabric comprising fiber layers each havinga different color, (j) shows the results wherein printing is performedon the surface of the non-woven fabric comprising fiber layers eachhaving a different color, and coating is performed on the back surfacethereof simultaneously,

FIG. 7 illustrates the shapes of the non-woven fabric for interiormaterials manufactured in accordance with an embodiment of the presentinvention at each process, whereas (a) shows the surface of thenon-woven fabric, (b) shows the printed surface of the non-woven fabric,and (c) shows the surface of the non-woven fabric which was subject tothe alkaline etching process after printing,

FIG. 8 illustrates an example wherein the alkaline etching processednon-woven fabric for interior materials is used for a ceiling materialof automobiles,

FIG. 9 illustrates the steps of the coating process, whereas

(1) shows a binder,

(2) shows a first roller,

(3) shows a second roller,

(4) shows a gauge,

FIG. 10 illustrates the steps of the printing process according to anembodiment of the present invention, and

FIG. 11 is a graph illustrating the comparison of the absorptioncoefficient (α) of the non-woven fabric for interior materials, withrespect to the frequency bandwidths before and after the alkalineetching process. The red color represents the non-woven fabric after thealkaline etching process, and the blue color represents the non-wovenfabric before the alkaline etching process.

DETAILED DESCRIPTION

In the present invention, it was discovered that a wet etching methodusing an alkaline solution, such as NaOH, is simple, quick, and easy tocontrol the processing. Moreover, the apparatuses and chemicals used arelow in price and it may be helpfully used for a large amount of work.Accordingly, it was discovered that there is a need in the art for amethod for acquiring various appearances while using the wet etchingmethod.

According to the present invention, the interior skin materials forautomobiles can be manufactured with various external appearances, goodabrasion resistance and good moldability by performing pre-treatmentprocesses, such as coating or printing the non-woven fabric,independently of the etching process, to form various externalappearances. In addition, after such pre-treatment processes, subsequentalkaline etching on the non-woven fabric has been found to enhance thesound absorbing properties of the interior materials for automobiles.

In an embodiment, the present invention solves the afore-mentionedproblems, and provides a method for manufacturing a non-woven fabric forinterior materials for automobiles by performing an alkaline etchingprocess in a regular shape together with various pre-treatment processessuch as coating or printing processes on the surfaces of the non-wovenfabric. As such, the present invention can provide a non-woven fabricwith an improved abrasion resistance and external appearance as well asan improved moldability and sound absorption properties.

In an embodiment, the present invention provides a non-woven fabric forautomotive interior materials and a method for manufacturing the same byperforming alkaline etching on the non-woven fabric in a regularpattern, along with pre-treatment processes, such as various coatingsand printings on the surfaces of the non-woven fabric.

In an embodiment, the present invention provides a method formanufacturing a non-woven fabric by printing a surface or a back surfaceof the non-woven fabric and then performing an alkaline etching processon the surfaces of the non-woven fabric.

In accordance with this method, it is preferable to coat the surface orthe back surface of the non-woven fabric before the printing process.

In accordance with this method, it is more preferable to perform analkaline etching of non-woven fabric after the printing process, thecoating process, or a combination thereof repeatedly.

In accordance with this method, it is preferable that the non-wovenfabric comprises between 2 and 5 fiber layers.

In accordance with this method, the coating process is performed byusing a binder comprising at least one selected from the groupconsisting of acryl, styrene, polyvinylchloride, polyvinyl alcohol,polyester, ethylenevinylchloride, ethylenevinylacetate and polyurethane.

In accordance with this method, it is preferable that the alkalineetching process is performed with respect to greater than 50% to lessthan 90% of a surface area of the non-woven fabric.

In accordance with this method, it is preferable that the alkalineetching process is performed by using any one selected from the groupconsisting of NaOH, KOH, RbOH and CsOH, and more preferably by usingNaOH.

In accordance with this method, it is preferable that the fiber layersof the non-woven fabric comprise polyester of 50-100 wt. %.

In addition, the present invention provides a non-woven fabric forinterior materials for automobiles manufactured by any embodiment ofthis method.

In an embodiment, the present invention provides a method formanufacturing a non-woven fabric for interior materials of automobilesby performing an alkaline etching process on a surface of the non-wovenfabric in a desired pattern so that the color of the etching processednon-woven fabric itself can appear, and printing the surface or the backsurface of the non-woven fabric before the etching process.

The etching process is used to melt a surface of a fiber in a regularpattern so that a unique three-dimensional appearance may show up. Sincethe surface of the fiber is melted in a regular shape and depth with astrong alkaline material, the etching process is suitable for thenon-woven fabric with a thick fiber layer compared to thin textilefabrics. In addition, since the textile fabrics are woven with warps andwefts, the warps or the wefts are cut during the etching process, and,thus, the strength of the textile fabrics is significantly lowered.However, since the non-woven fabric is entangled with a large number offiber strands, even if any portion thereof is damaged by processes,neither the tensile strength nor the abrasion strength is seriouslydeteriorated. Accordingly, the etching process is a suitable method formanufacturing the non-woven fabric.

According to an embodiment, the present invention uses an alkalinematerial for the etching process to form three-dimensional patterns onthe surface of the non-woven fabric in a regular shape and depth so thatthree-dimensional structures are formed on the surface of the non-wovenfabric, whereby the sound absorbing properties are significantlyimproved compared to the non-woven fabric of the same weight. Inaddition, the surface of the non-woven fabric is melted in a regularshape and depth to remarkably reduce a high tensile elongation and amodulus of the non-woven fabric, thereby enhancing the moldability ofthe non-woven fabric.

However, if only the etching process is performed, since the regularpatterns formed by the melting of the surface of the fiber exhibit thesame color as the non-woven fabric, it is difficult to obtain variousshapes. Therefore, to solve this problem, various external appearanceswere obtained by performing the printing process before the etchingprocess, and a larger variety was obtained by performing an additionalcoating process before the printing process. In addition, as a coatinglayer or a printing layer was added by such a pre-treatment process, theabrasion strength and the dimensional stability was increased, and as asurface area was increased, the sound absorbing properties wereimproved. FIG. 6 shows an example obtained by performing a combinationof various pre-treatment processes.

The present invention forms a non-woven fabric with at least two fiberlayers of different colors so that such different colors may appear onthe respective fiber layers in a sequential manner, thereby obtaining anon-woven fabric for interior materials with various patterns andcolors.

The non-woven fabric is a type of fiber, which is not woven by warps andwefts like cloth, but instead manufactured by spreading a fiber of aregular thickness and length thinly and broadly by a carding process andthen laminating the fiber one after another in several layers at adesired weight and width by a web forming machine. Accordingly, sincemore than five carding machines and web forming machines must beinstalled to obtain more than five fiber layers with different colors,an excessive investment cost could be incurred and thus may be currentlyeconomically unfeasible. Thus, it is preferable that said fiber layersare greater than two layers and less than five layers.

The printing or coating process may be performed as a pre-treatmentprocess before the etching process. The printing or coating process maybe performed, either alone or in combination thereof, on the surface orthe back surface of the non-woven fabric. The printing process means toprint the surface of the non-woven fabric with a desired pattern orcolor. The printing process may be performed by a rotary screen method,a flat screen method, or an offset method. In addition, if the coatingprocess is additionally performed before the printing process, morevaried external appearances can be obtained compared to performing onlythe printing process, by allowing various colors different from thecolor of the non-woven fabric itself to be exhibited.

Advantageous Effects Include the Following:

According to an embodiment, the present invention performs printing andcoating processes at least two times in a short time to form a varietyof patterns on the surface of the non-woven fabric at a low cost,thereby imparting a three-dimensional effect and improving designproperties. Due to such pre-treatment processes, the present inventionenhances the abrasion resistance, obtains various external appearances,improves the tensile elongation by the etching process, andsignificantly improves the moldability by reducing the modulus.Accordingly, the present invention solves the problem of the prior artthat the conventional coating or printing process reduces themoldability by forming various external appearances. Furthermore, thepresent invention increases the surface area of the non-woven fabric bythe etching process to significantly enhance the sound absorbingproperties. In other words, such various external appearances areobtained by the printing or coating process, and the improvements in thephysical properties, such as the sound absorbing properties and themoldability, are achieved by the etching process. Accordingly, thepresent invention can provide a non-woven fabric for interior materialsfor automobiles with a variety of functions which are recently neededfor the interior skin materials for automobiles.

The present invention is described in detail below by means of exemplaryembodiments, but the embodiments are purely illustrative, and are not tobe interpreted as limiting the scope of the present invention.

The non-woven fabric for interior materials in accordance with thepresent invention can be manufactured by pre-treatment processes, suchas printing or coating processes, and the etching process.

Coating Process:

The processes of a chemical coating (or binder coating) of the presentinvention is shown in FIG. 9.

The coating apparatus comprises a pair of rollers, and one or bothsurfaces of the non-woven fabric may be coated by at least one coatingapparatus. If the non-woven fabric passes through between the pair ofrollers which are rotating in opposite directions based on the centralaxis, a binder is added to a surface on which one roller and thenon-woven fabric are adjacent to each other, so that the surface of thenon-woven fabric is coated with the binder. ACRYSOL 890, AcrylicEmulsion DK-6800 DK Chem or EW-100S SKI PET RESIN, available from DKC,are examples of binders that can be used.

At this time, the surface of the non-woven fabric contacting the tworollers may be the same (front surface coating), or may be different(back surface coating). In addition, if the front surface coating andthe back surface coating is performed simultaneously, a double surfacecoating is possible. That is, the double surface coating can be made byperforming the back surface coating by a pair of rollers, drying thecoated back surface, subjecting the dried non-woven fabric to the frontsurface coating by another pair of rollers, and drying the non-wovenfabric again. In other words, the back surface coating is performed insuch a manner that the non-woven fabric passes through a first roller,the opposite surface of the surface adjacent to the first roller passesthrough the second roller, and the binder is introduced between thesecond roller and the surface adjacent to the non-woven fabric. The foambinder is 50-500 g/l, a coating amount is 5-50 gsm, and the gaugedistance between the two rollers of the coating apparatus is 0 T-5 T.

Printing Process:

The printing process using a rotary screen method uses a printing unitin which a rotary screen contacts a guide roll (FIG. 10). As thenon-woven fabric passes through between a rotary screen roll (a in FIG.10) and a guide roll (b in FIG. 10) of a first-color printing unit, acolor binder (e in FIG. 10) exhausted through a binder provider (c inFIG. 10) installed within the rotary screen roll is pressed by a squeezebar (d in FIG. 10) so that a portion thereof is discharged out of theexternal surface of the rotary screen, whereby patterns are formed onthe surface of the non-woven fabric. Since the squeeze bar is positionedwithin the scope of magnetic field of a magnet (an electromagnet) (f inFIG. 10), a predetermined amount of color binder is discharged by thesqueeze bar to the outside of the rotary screen in a predeterminedposition, thereby allowing for printing. At this time, the resolution ofa print pattern can be controlled by adjusting the magnetic fieldintensity of the magnet to 3-8 kgf. If the magnetic field intensity ofthe magnet is high, the pattern is dark and vivid, and if the magneticfield intensity thereof is low, the pattern is printed faintly.

A printing unit (second-color printing unit) of the same type as saidprinting unit is additionally installed at the side, and if thenon-woven fabric passes through the first-color printing unit andsuccessively moves to the second-color printing unit, additionalpatterns are formed. As such, different external appearances areobtained through at least two times of successive processing, and thenon-woven fabric is printed with a desired color by mixing the binderwith a dye and an inorganic pigment at an amount of 1-10 wt. % withrespect to a total weight of the binder. Foron Black RD-3G 300(available from Clariant, Swiss), or Foron Dark Blue RD-2RE 300(available from Clariant, Swiss), are examples which can be used for thedye, and RYUDYE-W BLACK RS CONE, RYUDYE-W NAVY BLUE FFTR, RYUDYE-W REDFFGR, RYUDYE-W YELLOW FF3R or RYUDYE-W BROWN FFR (manufactured by DIC,Japan) are examples which can be used for the inorganic pigment.

The guide roll is formed of a soft material, such as rubber or silicon,so as to reduce a thickness deviation of the non-woven fabric, wherebythe surface of the non-woven fabric is printed in a regular thickness.In addition, an open area, in which a print screen is open in a regularpattern so that the binder is escaped to be printed, is about 40-90% ofthe surface area of the non-woven fabric.

A dye in the form of fine powder is dispersed in water in asubstantially colloid state by a dispersing agent to prepare a dispersedye, and the dye is dissolved in the fiber to be dyed on the fiber.

As above, through at least two times of successive printing process, thenon-woven fabric is printed with different patterns and colors inaccordance with a mixing ratio of the dye and the pigment, wherebyvarious external appearances are obtained.

Alkaline Etching Process:

An alkaline etching process is performed on the surface of the non-wovenfabric formed of polyester of 100 wt. %. The alkaline etching process isperformed by adding a strong alkaline material, NaOH, on the surface offiber to melt the fiber in a regular shape and depth. After printing thesurface of the non-woven fabric with an alkaline material, the printingsolution and the melted portion of the non-woven fabric are separated.

The moldability and the sound absorption properties of the non-wovenfabric for interior material manufactured as above were measured.

Comparison of Moldability:

To confirm the effect of the alkaline etching process on the moldabilityof the non-woven fabric, the modulus was compared before and after theetching process.

TABLE 1 Before the Etching After the Etching Process Process 25%Longitudinal 25.0 8.1 modulus Direction (MD) (kgf/5 cm) Transverse 11.09.3 Direction (CD)

In Table 1 above, the term “25% modulus” is an important physicalproperty to evaluate the moldability, which means a force required toextend a predetermined length of the non-woven fabric by 25%. Thus, themoldability is better as the value is lower. As shown in Table 1 above,the modulus of the non-woven fabric has been significantly lowered afterthe etching process than before. In particular, the modulus in thelongitudinal direction has been decreased by 30% than it was before theetching process.

Comparison of Sound Absorbing Properties:

To verify the effect of the etching process on the sound absorbingproperties of the non-woven fabric, the sound absorption properties werecompared for the respective frequency bandwidths before and after theetching process. The sound absorbing properties of the etching processednon-woven fabric are excellent throughout all the frequency bandwidthsthan they were before the etching process, and in particular it wasconfirmed that the sound absorbing properties were remarkably improvedin the frequency bandwidths of greater than 1000 Hz (FIG. 11).

The present invention may be used for interior skin materials forautomobiles, and for materials for shoes which is manufactured bymolding skin materials and a substrate simultaneously for consistentquality and for mass production.

While the invention has been described with reference to particularembodiments thereof, it will be understood by those having ordinaryskill the art that various changes may be made therein without departingfrom the scope and spirit of the invention. Further, the presentinvention is not limited to the embodiments described herein; referenceshould be had to the appended claims.

1-10. (canceled)
 11. A method for manufacturing a non-woven fabric forautomotive interior materials, the method comprising: printing on atleast one of a front surface and a back surface of the non-woven fabric;and alkaline etching the front surface of the non-woven fabric.
 12. Themethod according to claim 11, further comprising coating the at leastone of a front surface and a back surface of the non-woven fabric priorto printing.
 13. The method according to claim 12, wherein the coatingis performed using a binder including at least one of acryl, styrene,polyvinylchloride, polyvinyl alcohol, polyester, ethylenevinylchloride,ethylenevinylacetate and polyurethane.
 14. The method according to claim12, the coating and the printing are performed repeatedly prior to thealkaline etching.
 15. The method according to claim 11, wherein theprinting is performed repeatedly prior to the alkaline etching.
 16. Themethod according to claim 11, wherein the non-woven fabric includesbetween 2 and 5 fiber layers.
 17. The method according to claim 11,wherein the alkaline etching is performed on between 50% and 90% of atotal area of the front surface of the non-woven fabric.
 18. The methodaccording to claim 11, wherein the alkaline etching is performed usingat least one of NaOH, KOH, RbOH, and CsOH.
 19. The method according toclaim 18, wherein the alkaline etching is performed using NaOH.
 20. Themethod according to claim 11, the non-woven fabric includes fabriclayers including polyester between 50 and 100 percentage weight.
 21. Anon-woven fabric for automotive interior materials, comprising: a frontsurface and a back surface, at least one of the front surface and theback surface including print, the front surface including alkalineetching.